In 1505, the city of Florence commissioned its treasured artist, Leonardo da Vinci, to paint a sprawling fresco depicting the city’s victorious battle with the Milanese in 1440. Da Vinci, who was known to detest war, eventually abandoned the project, leaving the scenery of military men on horses to vanish forever. Or so they thought.

Teaming up with a few scientists, art historians are claiming that they may have uncovered evidence of da Vinci’s lost fresco, concealed by another painting in Florence’s city hall, Palazzo Vecchio, MSNBC reports. The project, known to some as “Lost Leonardo,” sparred debate in the art world over whether it still existed — and if researchers should drill holes into Giorgio Vasari’s historical fresco, “The Battle of Marciano,” to see if their theory could be proven right.

But with the help of high-tech tiny video probes, the U.S. National Geographic Society, the Center of Interdisciplinary Science for Art, Architecture and Archeology at the University of California at San Diego, and Italian art experts carefully worked through existing cracks in the Vasari fresco to find traces of pigments known only to be used by da Vinci. Maurizio Seracini, one of the experts said although evidence is still inconclusive, the “data is very encouraging.”

“All of the holes that were put into the mural were either in areas that had been previously restored or in fissures, so the original Vasari was not touched,” he added.

Seracini, an engineer and expert in art diagnostics, said he believes Vasari might have wanted to preserve da Vinci’s work, which was painted during the height of his career, by placing a thin wall several centimeters from where Vasari painted his own mural. The researcher came up with the theory upon finding a soldier in Vasari’s fresco holding a small flag with the emblazoned words, “He who seeks, finds,” the BBC reports.

But some art experts are unconvinced. Tomaso Montanari, an art historian who opposes the project, finds no merit in the so-called discovery. “What do they mean by saying the findings are compatible with Leonardo? Any painting from the Renaissance would be,” he told the BBC. “Anything from that era could be painted on that wall. What lacked here is a neutral team that has the scientific authority to evaluate this.”

For now, the researchers emphasize the findings are merely preliminary, and the evidence remains inconclusive. Italy’s culture ministry must decide whether the team should proceed exploring other parts of the painting and risk preservation of the historial could-be-facade that is Vasari’s fresco. While art historians continue to debate over the validity of the theory, Florence Mayor Matteo Renzi told MSNBC he believes da Vinci’s unfinished painting does in fact exist behind the wall. With the help of modern science, he contends, perhaps the world could enjoy both works of art. “But if I had to choose,” he added, “I would choose Leonardo.”